Permanent magnet type rotary electric machine

Abstract

For providing a permanent magnet type rotary electric machine that can reduce magnetic fluxes concentrated to one side in rotating direction on a magnetic pole circumferential face that causes torque ripple as well as ensure the mechanical strength, in the present invention, an outer circumference of respective magnetic poles is formed in a circular arc having a same curvature as well as the magnetic pole center axes of the respective magnetic poles are displaced with respect to the rotation center of a rotor so that an air gap between a stator and the respective magnetic pole outer circumferences at one side in the rotating direction is widened in comparison with the air gap at the other side.

1. A permanent magnet type rotary electric machine comprising:
 a stator; and 
 a rotor that is born in free of rotation with respect to the stator via an air gap, and in which an even number of cooling use ventilation passages extending in axial direction are formed in a rotor core of the rotor along the circumferential direction with an interval, and an even number of magnetic poles constituted by burying permanent magnets in the rotor core between the adjacent cooling use ventilation passages along the circumferential direction, and the rotor is rotated in one direction, 
 wherein the outer circumference of the respective magnetic poles of even number is formed in a circular arc, the circular arc of each of the respective magnetic poles having a same curvature, and a magnetic pole center axes of the respective magnetic poles are displaced with respect to the rotation center of the rotor so that the gap between the stator and the respective magnetic pole outer circumferences at the rear end side in the rotating direction is widened in comparison with the gap at the top end side. 
 
     
     
       2. A permanent magnet type rotary electric machine according to  claim 1 , wherein the circular arcs formed on the outer circumferences of the respective magnetic poles are respectively formed in an circular arc having a same radius. 
     
     
       3. A permanent magnet type rotary electric machine according to  claim 1 , wherein the circular arcs formed on the outer circumferences of the respective magnetic poles are respectively formed in an circular arc having a same radius, and the respective magnetic poles are formed by slanting its magnetic pole center axis toward one side in the rotating direction. 
     
     
       4. A permanent magnet type rotary electric machine according to  claim 1 , wherein the circular arcs formed on the outer circumferences of the respective magnetic poles are respectively formed in an circular arc having a same radius, and the respective magnetic poles are formed by displacing its magnetic pole center axis toward one side in the rotating direction in parallel with respect to the center line passing the rotating center of the rotor. 
     
     
       5. A permanent magnet type rotary electric machine according to  claim 1 , wherein the circular arcs formed on the outer circumferences of the respective magnetic poles are respectively formed in an circular arc having a plurality of radii. 
     
     
       6. A permanent magnet type rotary electric machine according to  claim 1 , wherein the circular arcs formed on the outer circumferences of the respective magnetic poles are respectively formed in an circular arc having a plurality of radii, and the respective magnetic poles are formed by slanting its magnetic pole center axis toward one side in the rotating direction. 
     
     
       7. A permanent magnet type rotary electric machine according to  claim 1 , wherein the circular arcs formed on the outer circumferences of the respective magnetic poles are respectively formed in an circular arc having a plurality of radii, and the respective magnetic poles are formed by displacing its magnetic pole center axis toward one side in the rotating direction in parallel with respect to the center line passing the rotating center of the rotor. 
     
     
       8. A permanent magnet type rotary electric machine according to  claim 1 , wherein axial direction cooling passages are formed at the inner diameter side from the portions where the permanent magnets are buried in the rotor core and in parallel with the cooling use ventilation grooves. 
     
     
       9. A permanent magnet type rotary electric machine according to  claim 1 , wherein radial direction ducts are formed in the rotor core at a plurality of portions in axial direction. 
     
     
       10. A permanent magnet type rotary electric machine according to  claim 1 , wherein axial direction cooling passages are formed at the inner diameter side from the portions where the permanent magnets are buried in the rotor core and in parallel with the cooling use ventilation grooves as well as radial direction ventilation ducts that communicate with the axial direction ventilation passages are formed in the rotor core at a plurality of portions in axial direction. 
     
     
       11. A permanent magnet type rotary electric machine according to  claim 1 , wherein in each of the magnetic poles of the rotor two permanent magnets of flat plate having a rectangular cross section are disposed in parallel in circumferential direction with an interval. 
     
     
       12. A permanent magnet type rotary electric machine according to  claim 1 , wherein in each of the magnetic poles of the rotor two permanent magnets of flat plate of a circular arc shaped cross section are disposed in parallel in circumferential direction with an interval. 
     
     
       13. A permanent magnet type rotary electric machine according to  claim 11 , wherein the flat plate permanent magnet is divided in axial direction. 
     
     
       14. A wind power generation system, wherein the system uses a permanent magnet type rotary electric machine according to  claim 1  as a generator, wherein the permanent magnet type generator is disposed inside a windmill nacelle, is connected rolatably to a windmill and electronically connected to a load via a power converter.